People who live along arroyos learn to love these rivers of sand.

Once or twice a year, or in dry times only once every few years, they become raging torrents of water that can rearrange the channel in minutes and uncover long-hidden layers of rocks, fossils and artifacts.

But most of the time, they provide sustenance and shelter to a variety of trees, brush and flowers; straight-aways and feeding grounds for coyotes, rabbits, birds, reptiles and insects; and refuge for humans.

Santa Fe architect Beverley Spears will discuss the Arroyo de los Chamisos, Santa Fe's largest watercourse after the Santa Fe River, on Tuesday afternoon at the School for Advanced Research.

People who come to New Mexico from wetter climes — Spears moved to Santa Fe in 1974 via Indianapolis, New Orleans, Philadelphia and Houston — might ignore what she calls "humble and sometimes maliciously maligned arroyos."

But after moving to a house near the Arroyo de los Chamisos and taking daily walks there for more than two decades, Spears self-published last year a 117-page book called Sand River in Bloom.

It includes Spears' photographs of the arroyo at different times of the years, her personal observations there and her warning that without conscious preservation, an arroyo can become an "urban wasteland or a dull monoculture of Siberian elms."

Spears' book focuses on the flora with a two-page "Blooming Time Table" that tracks when dozens of native species are in bloom — red-stemmed filigree from early April to early July, scarlet Indian paintbrush from early May to mid September, and chamisa (either an a or an o is acceptable at the end) from mid September to mid October.

You can buy Sand River in Bloom via blurb.com for $36.95 softcover, $44.95 hardcover with dust jacket and $47.95 hardcover with image wrap; read the single reserve copy in a locked case at the Southwest Room of the Main Public Library on Washington Avenue; or hear about it and see some of the slides during Spears' presentation from 3 to 4 p.m. Tuesday in the board room of the School for Advanced Research, formerly the School of American Research, 660 Garcia St. The free lecture is co-sponsored by the Historic Santa Fe Foundation as part of its 50th anniversary celebration.

The Arroyo de los Chamisos originates in the area called La Barberia in the mountains east of Santa Fe, enters the Santa Fe municipal limits at the Wilderness Gate subdivision and exits past the newly annexed areas of Las Soleras and Entrada Contenta. A new city street leading to a proposed commercial complex to be called The Crossing is misspelled on street signs as "Crossing at Chasimo." Spears' study is restricted to a 1-mile section — from Old Santa Fe Trail to Conejo Drive — encompassing about 47 acres on the southeast side of town.

In an interview, Spears said she wrote the book to call attention to preserving arroyos.

"It was fun and interesting learning about plants, but ultimately it was a preservation [effort] to make people realize the outstanding beauty and ecological value of that area and to protect it and not to mess it up," she said.

"They're dynamic in how they move. They move laterally and vertically and so, when you start building near them, when human beings do that, they don't normally do it very well, and then they have to damage the arroyo to protect their building investments."

Contact Tom Sharpe at 986-3080 or tsharpe@sfnewmexican.com.

IF YOU GO

What: Presentation on the Arroyo de los Chamisos

Who: Beverley Spears

When: 3-4 p.m. Tuesday

Where: School for Advanced Research, 660 Garcia St.

Admission: Free